In each of the questions, a sentence is divided into

Solution

B- In this part of the sentence, the noun ‘province’ i.e singular, is preceded by a plural noun, i.e. ‘countries’; thus in order to make the sentence grammatically consistent, we need to use both nouns in their plural form. C- The verb ‘depend’ is strictly followed by the preposition ‘on’. You can always depend ‘on’ something, rather than ‘in’ something. E.g: I can always depend ‘on’ you for my secrets OR I can always confide ‘in’ you. - Both the sentences ultimately mean the same but use different sets of words. Correct Sentence : While COVID-19 makes no difference between rich and poor, countries and  provinces , a lot can depend  on  the treatment where the person is when it comes to quality and cost of treatment.